Cutting tool



F. P. MILLER CUTTING TOOL April 13, 1937.

Filed April 19.- 1955,

FRA/VK HIV/LL ER Patented Apr, 13, 1 937 UNETED STATES PATENT OFFICE I 12 Claims.

This invention relates to cutting tools of the type employing inserted blades and the application will be found to feature in part matter divided out of my earlier application, Serial 614,823,

which eventuated in Patent Number 2,021,668.

Briefly, the invention provides an inserted blade cutter in which each blade thereof has a dovetail engagement with only one side of the associated blade receiving slot while the other side of the blade extends approximately at right angles to the bottom of the slot and is securely engaged by a locking means by which the blade is held in place, this arrangement allowing increased crosssectional area and consequently greater strength on the part of the blade and at the same time achieving an addition to the cutting surface of the blade.

Another aspect of the invention has to do with the blade locking means which will be found to provide for urging the blade locking pin thereof inward or in the same direction that the blade is urged by the end thrust accompanying operation, as distinguished from other cutters in which the blade locking means acts in opposition to the thrust of the cut and for that reason does not operate with maximum efficiency in securing the blade in adjusted position.

The invention also contemplates a novel mounting for a blade adjusting screw and by way of brief preliminary reference to this phase of the invention it is pointed out that the socket or opening in the cutter body for the reception of the screw breaks through one corner of the blade receiving slot, as distinguished from breaking through only one side wall thereof with the result that in all operative positions of the screw, the screw has a generous interlocking engagement with the body of the cutter while at the same time the longitudinal center of the screw is located in the slot for vpressure relation with the associated blade. In addition, the mounting for the blade adjusting screw provides for relatively increased blade travel or adjustment and thus obtains maximum use of the costly metal comprising the blade.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawing, forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a group perspective of a cutter block embodying the invention,

Figure 2 is a plan view of the cutter block, a portion of the block being broken away,

Figure 8 is a perspective of a. threaded bushing shown in section in Figure 7.

In the drawing, wherein for the purpose of illustration are shown several preferred embodiments of the invention, the numeral I 0 designates a cutter block of the type adapted to be mounted in a boring bar or, other support. As shown in Figures 1 and 2 the body I0 is formed in opposite sides thereof with diagonally extending slots l2 opening out through the opposite terminals of the body for the reception of blades M.

It isillustrated in Figures 3 and 4 that one longitudinal side of each blade M has a dove-tailed contact I6 with the opposed side wall of the associated slot, while the other longitudinal side or edge of the blade is lacking in such dove-tailed fit, andin fact, extends approximately at right angles to the surface plane of the block and to the bottom wall of the associated slot, giving to the with a longitudinal groove mating with a more or less similar groove 22 in the opposed side wall of the slot l2 for the reception of a cylindrical locking pin 26.

Referring now to Figure 3, it will be seen that a locking screw is threaded through the block at the front side of the associated blade and is provided between the ends thereof with an annular groove 32 defining a transversely curved annular shoulder for pressure contact with the adjacent locking pin 26. Thus, advancement of the screw 30 brings about transverse movement of the looking pin into binding engagement with the associated blade.

Now, it is also clearly illustrated in Figure 3 that the forward portion of the set screw 30 is provided with left-hand screw threads which are, of course, the reverse of the threads ordinarily found on the corresponding parts in inserted blade cutting tools. This arrangement requires that advancement of the set screw be brought about by the left-hand turning of the screw.

1 Such left-hand turning of the set screw has the ,gag'eme'nt with; the surrounding wall of the anacute angle to each other.

effect of moving laterally the adjacent locking pin and at the same time urging the pin inwardly or rearwardly, thereby exerting a rearward or seating force on the associated blade. The force thus applied to the blade acts in the same direction as the end thrust. of the cut and thus acts in concert with s'uch'thrust as distinguished. from the outward and unseating influence exertedbya right hand thread on the screw. The forward portion of the set screw 30 is shown to be provided with a tool engaging means in the nature of a screw driver groove 38 so that thread, advancement of the screw is conveniently accomplished by turning the screw driver to the right as is customary. i

As shown in Figures 1 and 2-, eachblade is en gaged at the rear end-thereof by a thrust screw '50 and such thrust screw is threaded into an opening or socket 52 in 'the block. It is important to observe that the opening-52 opens for substantially less than 90 degrees into theblock l2 so that the set screw is prevented from shifting laterally from the socket 52 into the blade slot.

Attention is invited'to Figure 2 inwhich it is illustrated that the opening or socket 52 breaks through that longitudinal corner of the blade slot l2 in which the walls of such corner are at Hence, while less than a quarter of the circumference of the screw is exposed and left without bracing, substantially more thana quarter of the cross-sectional area of the screw, including the axial centerfof the screw is in the slot for pressure engagement at the forward end thereof with the blade. This arrangement, leaves substantially more than '270 degrees of the'threadedcircumference of the screw in thrust transmitting interlocking en socket 52. a s r v QAlso, by causing the opening .52 .to break through adjoining wall'sof thefslojt, as distin+ guis'hedfrom breaking through but'one wall,

, there is avoided. appreciable}weakeningQof,the

block due'to thepresence of the opening. 1 v

The mounting of the screw 50 hol'dsflthe screw in full functioning position even "though, it has been adjusted far beyond its "originafp'osition and has come to be vlocated between the-ends of, the blade receiving slot. That is to say, the break in the sidewall of the sock'et or hole 52 is less than 90 leaving substantiallymore than 270 of the circumference of the screw surrounded and in intimate threaded engagement with the material formingthe block. I By" reason of this arrangement, the screw is positively held against lateral slipping or shifting into theblade receiving slot or losing the intended close fit I with the surroundingthreads, thisbeing-true regardless of the position to which thescrew iszadvanced. This blade mounting is particularly advantageous. not only because of the security with which'the screw is held in place, but;also,since it -makes possible an unusual amount of, blade 7 b adjustment. and wear. -,'Ihat;is,to .say, regardless of the, adjustment of the screw. or the extent to which itis-advanced, it remainsin functioning position :in full threaded engagement for ,sub-

:stantially. the (entire. length thereof 7 with the sur rounding wall of the socket 52. 1

ao iaoee is in the nature of a cutter block in which body ;fltting left hand threads necessitating counterclockwise rotation of the screw to advance the screw and turn the screw in the direction necessary to urge the locking pin and the blade toward the said inner end wall of the slot while at the same time, forcing the trailing side of the blade firmly against the back side of the slot.

- That is to'say, by this arrangement, the trailing side of the blade has effective thrust transmit ting contact withthe' back side of the slot and at the'same'time the'screw is turned in a counterclockwise'direction to advance the screwand thus-force the pin 26'laterally and-rearwardly,

thereby urging the blade rearwardly or in the same direction in which it is urged under the influence of the end thrust accompanying operation. Clearly, it is not feasible to locate the binding screw adjacent the trailing side of the blade because it is required that there be a firm thrust transmitting contact between the back side of the blade and the backside of the slot.

In the form of invention disclosed in Figures 5 and 6 theblock is designated by the numeral '80 and is providedwith a slot 82 for the a'djus table reception of a blade 84. In this form ofinvention the cross-sectional form of the blade and the slot may be the same as that shown in F gures l to 4 inclusive. One. side wall of the 46 slot 82 is formed with a recess '86 receiving a locking bushing 88 of segmental form and; having 'a flat side'presented tothe blade and formed' with a rib '90 projecting into a groove in the adjacent sideof the blade.

ing engagement with the blade. Itwillbe seen thatthe rib 90 functions after the fashion of the pin 26 shown in Figures lto 4 a'ndthus serves as 'a pressure transmitting medium between the bushing 88 and the adjacent'blade, urging the 7 blade laterally, and inward into pressure contact with the back and bottom walls of the slot.

V 1. A toolxcarrying block for use in a boring. bar comprising a body having aslot provided with longitudinal walls at acute anglesjto each other thereby defining a longitudinal fcorner, a blade in said slot", said body being formed with a threaded opening overlapping the slot and extending along said longitudinal corner, and an axially adjustable screw in said opening'andhavmg more than 270 degrees of the circumference thereof surrounded by the wall of said threaded opening and having more'than a quarter of .the cross-sectional area thereof in said slot theforv A set screw 92 maybe employed to secure the bushing in flrm,lock- Ward end of the said screw being in abutting V relation ,to the inner end of said blade.

2. A tool carrying block for use in a boring bar comprising a body having a slot provided with Walls at acute angles to each other thereby defining a corner, a cutting blade in said slot, said body being formed with a threaded opening overlapping the slot and extending along said corner, and an axially adjustable screw in said threaded opening and having more than 2'70 degrees of the circumference thereof surrounded by the wall of said opening and having more than a quarter of the cross-sectional area thereof in said slot, and having the axial center thereof in said slot the forward end of said screw being in abutting relation to the inner end of said blade.

3. A tool carrying block for use in a boring bar comprising a body having a slot provided with side and bottom longitudinal walls defining a longitudinal corner, a blade in said slot, said body being provided with a threaded opening breaking through and extending along said longitudinal corner, and an axially adjustable screw in said opening and having more than 2'70 degrees of the circumference thereof surrounded for the full length thereof by the wall of said threaded opening and having the axial center thereof in said slot, the forward end of said screw being in abutting relation to the inner end of said blade.

4. In a block for use in a boring bar, a body having a slot provided with side and bottom lon- 30 gitudinal walls defining a longitudinal corner, a blade in said slot, said body being provided with a threaded opening overlapping and extending along said longitudinal corner, and an axially adjustable screw in said threaded opening and engaged for the full length thereof by the wall of said opening, said screw being extended into said slot in abutting relation to the inner end of said blade.

5. A tool carrying block for use in a boring bar 0 comprising, a body having a slot provided with an inner end and front and back sides, a blade in said slot and having leading and trailing sides, locking pin engaging the leading side of the blade, and a binding screw adjacent to 45 the front side of the slot and engaging the pin at a point between the ends of the slot, said body and said screw having interfitting left hand threads necessitating counter-clockwise rotation of the screw to advance the screw and turn. the 50 pin side of the screw in the direction of the said inner end of the slot and thus urge the locking pin and the blade toward the said inner end of .the slot and simultaneously force the trailing side of the blade firmly against the back side of 55 the slot, the forward portion of said binding screw being provided with means for engagement by an operating tool.

6. In a block for use in a boring bar, a body having blade receiving slots disposed diagonally -60 to the axis of the block, each of said slots being provided with a bottom wall and back and front side walls, the back side wall being at an acute angle to the bottom wall and the front side wall being at right angles to the bottom wall, blades 65 in said slots which in cross-section conform to the cross-sectional form of said slots, and looking means for each of said blades embodying a locking pin engaging the front side of the blade and a binding screw adjacent to the front wall 70 of the slot and engaging the pin at a point between the ends of the slot, said body and said screw having interfitting left-hand threads whereby advance of the screw will result in turning of the pin side thereof in the direction of 75 the inner end of the slot to urge the locking pin and the blade toward the inner end of the slot and simultaneously force the back side of the blade firmly against the back wall of the slot, the forward portion of said screw being provided with means for engagement by an operating tool.

7. A tool carrying block for use in a boring bar, comprising a body having upper and lower sides and a blade receiving slot opening through one of said sides, said slot being provided with front and back longitudinal side walls, a blade in said slot and having leading and trailing sides, the leading side of said blade and the front wall of the slot being formed with cooperating grooves, a locking pin in said grooves, and a binding screw engaging said locking pin at a point between the ends thereof, said binding screw and said body being formed with interfitting lefthand threads, the forward portion of said screw being provided with means for engagement by an operating tool for turning the screw, said means being accessible from the side of said body opposite that having the blade-receiving slot therein.

8. A tool carrying block for use in a boring bar comprising a body having a blade receiving slot disposed diagonally to the axis of the body and opening through one side thereof, a blade in said slot, said blade being provided with a groove along the front side thereof, a clamping member engaging said groove, and threaded means for actuating said clamping member, said threaded means being provided with a tool engaging portion accessible for operation from the side of said body opposite that having the blade receiving slot therein.

9. A tool carrying block for use in a boring bar comprising a body having a blade receiving slot opening through one side thereof, said slot being provided with front and back longitudinal side walls and a bottomwall, the back side wall of said slot being at an acute angle to the bottom wall and the front wall being at right angles to the bottom wall, a blade in said slot which in cross-section conforms to the cross-sectional form of the slot, said blade being provided with a groove along the front side thereof, a clamping member engaging said groove, and threaded means for actuating said clamping member, said threaded means being provided with a tool engaging portion accessible for operation from the side of said body opposite that having the blade receiving slot therein.

10. A tool carrying block for use in a boring bar comprising a body having a blade receiving slot opening through one side of the body, said slot being provided with front and back longitudinal side walls, a blade in said slot and having leading and trailing sides, the leading side of said blade being provided with a groove extending 'lengthwise of the blade, said body being provided at the front side of said slot with a socket opening into the slot, a locking bushing in said socket and having a rib projecting into the groove in said blade, and a locking screw extending into said body from the side opposite that containing the blade receiving slot and having threaded engagement with said bushing.

11. A tool carrying block for use in a boring bar comprising a body having a blade receiving slot opening through one side of the body, said slot being provided with front and back longitudinal side walls, a blade in said slot and having leading and trailing sides, the leading side of said blade being provided with a groove extending lengthwise of the blade, the lower wall of said groove being inclined to define a cam-like surface, said body being provided at the front side of said slot with a socket opening into the slot, a locking bushing in said socketand having a rib projecting into'the groove in said blade and engaging said cam-like surface, and a locking screw extending into said body from the side opposite that containing the blade receiving slot and'having threaded engagement with said bushing.

12. In a block for use in a boring bar, a body having a blade receiving slot provided with front and back longitudinal side walls and a bottom inner end of the slot.

wall, a blade in said slot, the'front longitudinal side Wall of said blade being formed with a groove running lengthwise thereof, a locking element projecting into said groove, and a binding screw threaded into said body and engaged with said locking element to urge ,the locking element and the blade downwardly toward the bottom wall of said slot, laterally toward said backtlongitudinal side wall of the slot and in the direction of the 

